I think this is a pretty cool experiment. And very worthwhile. The only slight flaw is the psychological effect of the participants knowing that they can choose to be let out if they want. They'll be discouraged from leaving, but if they insist then they'll be released. In the event of a medical emergency I would expect they'd also be released. And that dampens the realism of it.

This is really great to see some research being done on long term isolation and confinement. Besides being a simulation for a trip TO Mars, what about a simulated "habitat" on Mars? A kind of Biosphere 2 experiment I guess (or Biosphere 2.0 ) where they can research not only the humans but the plants and animals. Does anyone know of something like this in the works?